Featured Research

from universities, journals, and other organizations

Expression Of Infrared Fluorescence Engineered In Mammals

Date:
May 16, 2009
Source:
University of California - San Diego
Summary:
Researchers have shown that bacterial proteins called phytochromes can be engineered into infrared-fluorescent proteins. Because the wavelength of IFPs is able to penetrate tissue, these proteins are suitable for whole-body imaging in small animals.

This is the structure of an infrared fluorescent protein.
Credit: UC San Diego School of Medicine

Researchers at the University of California, San Diego – led by 2008 Nobel-Prize winner Roger Tsien, PhD – have shown that bacterial proteins called phytochromes can be engineered into infrared-fluorescent proteins (IFPs). Because the wavelength of IFPs is able to penetrate tissue, these proteins are suitable for whole-body imaging in small animals. Their findings will be published in the May 8 edition of the journal Science.

"The development of IFPs may be important for future studies in animals – to find out how cancers develop, how infections grow or diminish in mice, or perhaps how neurons are firing in flies," said Tsien, professor of pharmacology, chemistry and biochemistry at UC San Diego and a Howard Hughes Medical Institute investigator. Tsien was one of three scientists awarded the 2008 Nobel Prize in Chemistry for discovery of the Green Fluorescent Protein (GFP) and a series of important developments which have led to its use as a tagging tool in bioscience.

The limitation of using GFP in living mammals is that its wave lengths are not long enough to allow light to penetrate far enough to allow inner cells to glow with fluorescent light.

First author Xiaokun Shu, PhD, of the UC San Diego School of Medicine's Department of Pharmacology and the Howard Hughes Medical Institute, coerced the phytochrome from the bacteria Deinococcus radiodurans to fluoresce – the first protein to glow in infrared and work in mouse models. A phytochrome is a photoreceptor – a pigment that plants and bacteria use to detect light – which is sensitive to light in the red and far-red region of the visible spectrum.

"IFPs express well in mammalian cells and spontaneously incorporate biliverdin, a green pigment that is present in humans and other mammals," said Tsien. Biliverdin is the substance responsible for the yellowish-green color of a bruise as it fades, for example. Biliverdin normally has negligible fluorescence. However, Shu was able to coax the biliverdin-containing protein to fluoresce by cutting off the parts of the phytochrome that divert the energy of the light.

"We hoped that by doing so, the light's energy wouldn't go anywhere else but would instead go out and become fluorescent," Shu said, adding that the protein is "moderately fluorescent, but we still have a long way to go."

Tsien stated that, while this work is promising for future studies in animal models, he doesn't think it will be applied directly to imaging in humans for several reasons.

"First, all fluorescent proteins derived from corals, jellyfish, and now bacteria are powerful in basic research because they are encoded by a gene," said Tsien. "Introducing such genes into people would pose big scientific and ethical problems."

He explained that, secondly, humans are still too thick and opaque for the infrared fluorescence to get deep inside our bodies, although scientists can now see faintly through a mouse with infrared, because mice are so much smaller.

The Tsien lab is working on a different project to develop a technique without these limitations, one that can be used for imaging in humans. His hope is that, one day, people will be able to go in for their annual check ups and know if they have cancer because tumors will light up by magnetic resonance imaging of diagnostic molecules.

But for now, Tsien, Shu and their colleagues at UC San Diego hope that the prototype they have developed can be used to make other, improved fluorescent bacterial proteins from among the huge numbers harnessed from other organisms – IFPs that can be used in important animal studies.

This technology (SD2008-303) and related technologies are available for licensing and commercial development through the UCSD Technology Transfer Office.


Story Source:

The above story is based on materials provided by University of California - San Diego. Note: Materials may be edited for content and length.


Cite This Page:

University of California - San Diego. "Expression Of Infrared Fluorescence Engineered In Mammals." ScienceDaily. ScienceDaily, 16 May 2009. <www.sciencedaily.com/releases/2009/05/090507141353.htm>.
University of California - San Diego. (2009, May 16). Expression Of Infrared Fluorescence Engineered In Mammals. ScienceDaily. Retrieved September 1, 2014 from www.sciencedaily.com/releases/2009/05/090507141353.htm
University of California - San Diego. "Expression Of Infrared Fluorescence Engineered In Mammals." ScienceDaily. www.sciencedaily.com/releases/2009/05/090507141353.htm (accessed September 1, 2014).

Share This




More Matter & Energy News

Monday, September 1, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Australian Airlines Relax Phone Ban Too

Australian Airlines Relax Phone Ban Too

Reuters - Business Video Online (Aug. 26, 2014) Qantas and Virgin say passengers can use their smartphones and tablets throughout flights after a regulator relaxed a ban on electronic devices during take-off and landing. As Hayley Platt reports the move comes as the two domestic rivals are expected to post annual net losses later this week. Video provided by Reuters
Powered by NewsLook.com
Hurricane Marie Brings Big Waves to California Coast

Hurricane Marie Brings Big Waves to California Coast

Reuters - US Online Video (Aug. 26, 2014) Huge waves generated by Hurricane Marie hit the Southern California coast. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Chinese Researchers Might Be Creating Supersonic Submarine

Chinese Researchers Might Be Creating Supersonic Submarine

Newsy (Aug. 26, 2014) Chinese researchers have expanded on Cold War-era tech and are closer to building a submarine that could reach the speed of sound. Video provided by Newsy
Powered by NewsLook.com
Breakingviews: India Coal Strained by Supreme Court Ruling

Breakingviews: India Coal Strained by Supreme Court Ruling

Reuters - Business Video Online (Aug. 26, 2014) An acute coal shortage is likely to be aggravated as India's supreme court declared government coal allocations illegal, says Breakingviews' Peter Thal Larsen. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins